The most significant development in the weaving industry in recent years has been the on-board microprocessor control system. In recent years, microprocessors have been installed on-board individual weaving machines (e.g., "looms") to control the operation of the weaving machines. These on-board microprocessors are typically connected to a central minicomputer which monitors status data produced by the on-board microprocessors indicating, for example, machine stops, stop causes, speed efficiency and production rates.
Most such systems in the past have used unidirectional communications links between the weaving machine on-board microprocessor controllers and the loom monitoring system--that is, status data is communicated from the loom to the host processor, but control data is typically not communicated in the reverse direction back to the loom. In a few cases, off/on control of weaving machine signalling lights and the stop function has been achieved.
The deficiencies of these systems include: (1) the inability to control the set points of the independent, programmable variables of the weaving process except manually at each loom; (2) the inability to make style changes on single and multiple weaving machines digitally without sending a person to each machine, (3) the inability to optimize individual machines in a real-time manner, (4) the inability to analyze machine performance statistically in a real-time manner and to automatically adjust or stop the weaving machine, and (5) the inability to automatically signal auxiliary equipment or people (e.g., when a cloth roll needs to be doffed, when a filling package or warp needs to be delivered, or when a human technician needs to service the reed).
The concept of providing "bi-directional" data communications between a central processor controlling a weaving plant and mini-computers controlling individual weaving machines is known. See, for example, "Computerized Textiles' Second Stage Is Here", Textile World, pages 37-40 (November 1985). That article suggests bi-directional systems which control air-jet weaving machines, and describes three "levels" of bi-directional communication.
The first level involves signals, indicators and stopping of the weaving machine in order to improve productivity and quality (e.g., signalling a problem machine for too many stops, stopping a loom for doffing or for quality reasons, or flashing a lamp to tell the weaver to make corrections concerning the nature of warp stop).
The second level of bi-directional communications suggested by the Textile World article permits down loading of different settings required to operate a machine in a certain style, and requires a compatible interface (microprocessor) on board each weaving machine. This second level could, for example, set up an air-jet weaving machine to produce a certain style by instructing the machine on parameters for filling insertion, warp tension, stop positions, and the like.
The third level of bi-directional communications permits interactive control of individual weaving machines to, for example, determine if there are differences in settings of different machines, adjust the settings of a poorly performing machine, and report such interventional control in a log file.
While these three levels of bi-directional control have previously been suggested, the state-of-the-art loom monitoring and control systems available prior to the development of the present invention were not nearly so versatile. For example, in the Barco Automation System (manufactured by Barco Electric N.V. of Holland), a separate data collection and control "box" (designated DU4P) was required at each loom. This "box" had the following functions: (1) read a 12-bit status code generated by the loom to determine when a stop or start occurred, the cause of the start or stop, and the picks produced; (2) close a relay to turn on an indicator light or open a relay to turn a light off; (3) give an operator a message on a limited textural display; and (4) receive limited code inputs from the operator about stop causes or quality problems. This Barco system was incapable of influencing loom controls--all control by the loom monitoring system being through relays housed in a separate enclosure.
The following prior-issued U.S. patents are generally relevant in disclosing "bi-directional" monitoring/control systems utilized for purposes other than textile applications:
______________________________________ U.S. Pat. No. Inventor Issue Date ______________________________________ 4,090,248 Swanson et al May 16, 1978 4,135,181 Bogacki et al Jan. 16, 1979 4,446,458 Cook May 1, 1984 ______________________________________
Below is a non-exhaustive list of references disclosing electronic control systems for looms and weaving machines:
______________________________________ U.S. Pat. No. Inventor Issue Date ______________________________________ 4,364,002 Suzuki et al Dec. 14, 1982 3,570,550 Budzyma Mar. 16, 1971 3,613,743 Sakamoto Oct. 19, 1971 3,597,736 Best Aug. 3, 1971 3,414,905 O'Brien et al Dec. 3, 1968 874,724 Belgium Jul. 2, 1979 ______________________________________
The references listed below are generally relevant in disclosing various data monitoring systems:
______________________________________ U.S. Pat. No. Inventor Issue Date ______________________________________ 3,417,916 Broukel et al Sep. 8, 1964 4,536,849 Borish et al Aug. 20, 1985 4,382,287 Ackman et al May 3, 1983 4,356,475 Neumann et al Oct. 26, 1982 4,057,785 Furniss et al Nov. 8, 1977 3,641,326 Harte Feb. 8, 1972 3,566,355 Smith Feb. 23, 1971 3,491,340 Richman et al Jan. 20, 1970 3,323,107 DuVall May 30, 1967 3,293,605 Moore Dec. 20, 1966 3,059,238 Quinn Oct. 16, 1962 ______________________________________
While some efforts in the past apparently may have succeeded in producing automated loom control systems which include limited bi-directional communication of status and command signals between on-board loom microprocessors and a central computer, there is room for much additional improvement.
It would be highly advantageous to provide a real-time, distributed control system for weaving machines that is bi-directional and includes various advantageous features which improve overall system performance and product quality.
For example, it would be desirable to automatically and consistently achieve desired machine set-up, reduce machine down-time, reduce labor costs, produce higher productivity and quality of product, improve trouble shooting capability, and the like--all through automatic, reliable control processes.
On a somewhat more detailed level, it would be highly desirable to maintain various different "set-up" files or set points for different independent weaving variables like cloth style, and automatically execute style changes from such maintained set-up files. Statistical evaluation of monitored variables which results in the generation of out-of-control warning messages and/or interactive generation of corrective changes automatically would also be highly desirable. Automatic stopping of weaving machines as a function of monitored general processing conditions would improve product quality, as would automatic collection of data indicative of product quality inputted by roving inspectors via keyboards of individual weaving machines (or by automatically gathering data relating to product quality from each weaving machine). Automatic generation of suitable command messages to humans or other automated systems for service of individual weaving machines, and "smart" software algorithms for automatically generating new style set-ups would reduce weaving machine down-time and labor costs.
The present invention provides an interactive real-time, distributed control system for weaving machine control that is bi-directional and centrally manages the whole range of activities of a weaving room. Some of the advantages of the system of the present invention include:
Easy, consistent automatic machine set-ups;
Elimination of excessive machine down-time due to a person having to key in machine set-up data manually;
Reduction of labor related to weaving due to set-up changes;
Higher productivity and quality produced from optimized weaving processes;
Improvements related to trouble shooting and other diagnostic capabilities on a real-time basis through an interactive distributed control network; and
Less off quality since weaving machines are stopped automatically when out-of-control conditions occur and/or when significant deleterious statistical trends are detected (in previous designs, weaving machines would run out-of-control until a person detected the out-of-control operation and manually shut down the faulty machine).
In accordance with one aspect of the present invention, there is no need for a separate control box at each loom for data collection, since the invention allows data collection through an on-loom microprocessor which communicates bi-directionally with a central computer (the central computer having the capacity to efficiently store and analyze data collected from many looms). By eliminating separate data collection boxes at each loom, the costs of a separate enclosure, key pad, monitoring post and brackets, and the like, are eliminated; operator efficiency is increased (since operators do not have to use two different key pads and displays); the discrete control devices needed to control lights and machine stops are eliminated; wiring expenses are reduced (since there are not as many connections); and the entire data collection process is speeded up (thereby permitting rapid, real-time, interactive control of individual looms).
The present invention is also capable of real-time optimization of loom operating functions (e.g., the loom's programmable F functions--independent weaving variables) under software control. For example, loom filling arrival time is a function of main air nozzle pressure and pick release timing degrees. The present invention may increase or decrease main air nozzle pressure over a limited range in an amount which is related to the weaving style (i.e., to a targeted value) to control filling arrival time. If arrival time is still incorrect, then pick release timing degrees may be changed as needed to optimize the arrival time within a limited range.
The present invention also provides capability for changing machine set-up parameters, electrically and automatically, at a style change. In the present invention, the system host computer maintains current loom set-up data (e.g., F functions) by style and also contains (in a real-time register) the number of picks each loom must perform until the next style change. When a style change is requested, the new loom control information is automatically communicated to the loom on-board microprocessor and the changes are made automatically and electrically. This feature permits optimum set-up for a loom and style combination through the use of statistical techniques and a data base which maintains independent style set-ups by loom number. Set-ups can be made accurately and quickly at desired times. This feature is a great advantage over past situations, where a person had to go to each loom and key in all of these style change variables manually, often causing looms to remain idle for several hours awaiting service.
The present invention also performs statistical evaluation of monitored quality and performance variables to determine whether specific looms are out-of-control. If a loom is found to be out-of-control, diagnostic and corrective steps are automatically performed to improve control through control variable adjustment and optimization and/or exception messages are generated to alert personnel that manual trouble shooting is necessary. Such statistical evaluation and control occurs on a real-time basis, thus allowing higher efficiencies to be achieved. In addition, automatic collection of real-time direct and indirect labor data from each loom is gathered, thereby eliminating the need for frequency checks and time studies. Additionally, this data can be fed electronically into a labor data base for other uses (e.g., budget and labor standard determinations).
The gathering of real-time data from each loom also permits the interface of real-time data from the weaving process with automatic loom servicing equipment without the need for human intervention. For example, the central computer may determine whenever any filling package is empty (since all package transfers are detected)--and automatically arrange for a new filling package to be delivered to the loom.
The present invention also enhances control of dobby patterns. The central computer may automatically, electrically down load new dobby control data to individual looms as part of style set-up file transfer.
Looms may be stopped based on several conditions, including all or certain types of out-of-control conditions (e.g., when automatically gathered quality data from a loom indicates the quality of product being produced is inferior to that specified by quality data input by an operator); roll completion (i.e., a predetermined number of picks) insufficient supplied air pressure, the need for a style change, incorrect environmental conditions, and/or based on data already available on the loom beam being fed to the loom.
In accordance with another feature of the present invention, cut length (i.e., the number of picks on a cut or piece) may be controlled precisely. For example, when a customer requires exact cut lengths, the loom can be stopped automatically for a cut doff at the exact desired number of picks by transmitting a control communication message from the host computer to the particular loom. As another example, if precise cut lengths are not required, the centralized host computer can optimize the cut lengths based on the length of the loom beam supplied from slashing.
In accordance with another feature of the present invention, the host computer may predict the quality of the cloth being produced by a specific loom based on a variety of different variables, including quality of warp being used, the number and type of stops and "flags" (indications of loom operating conditions manually inputted by operators), how the particular filling lot is performing, quality data being inputted at each loom by human operators, and the like, and print a quality report for examination by the customer or by quality control personnel. Quality predictions can be statistically based and performed on a real time interactive basis.
In accordance with yet another feature of the present invention, data is gathered in real time describing the performance of each loom in operation (e.g., out-of-control performance and product quality). Real-time evaluation of this collected data may be used to predict when a specific loom needs service or a major overhaul, or when operators or other persons involved in operating and maintaining looms need retraining. Such information gathered in real time can also be used to provide incentives to such personnel based on product quality and/or loom performance. In addition, this collected data can be used to produce various useful listings (e.g., labor costs, material costs and system performance).